The invention relates to the storage and transportation of gas and more particularly to a device for the storage of gas under pressure permitting the storage and transportation of gas in a form that does not preliminarily require long and difficult treatment.
At present, gas is stored and transported in containers, in the liquid phase, or in the gaseous phase under pressure at ambient temperature.
The liquefaction of the gases is financially and energetically costly; particularly, in the case of hydrogen, the temperature is very low (20 K), the latent heat is high, and it is necessary to pass through an ortho-para transformation phase.
The storage under pressure (so called HP storage), for example about 200 bars, requires relatively heavy cylinders, for a relatively small quantity of gas. The increase in pressure (storage under very high pressure, or VHP) implies in the present state of the art, cylinders that are wound with filament, but these cylinders are very costly, and the compression means are not adapted for high flow rates; moreover, for a gas such as hydrogen, storage at 700 bars at 290 K represents only 225 Nm3 of gas per cubic meter of volume of the container, which is to say less than 60% of the volume in liquid phase at two atmospheres at absolute pressure (750 Nm3 of gas per cubic meter of volume of the container).
As a result, in such a case, the placing of gas under very high pressure is not of much interest.
The invention has for its object to overcome these drawbacks of the known devices, and more particularly to prevent storing, particularly for its transportation, the maximum of gas in the smallest volume and weight possible, at least cost.
To this end, the invention relates to a device for the storage of gas under pressure, characterized in that it comprises at least one container for the gas of the high pressure type, comprising an outlet conduit with which is associated a means ensuring a closeable calibrated loss, the gas being in the gaseous condition in this container over a range of pressures extending from about 40 to 250 bars and preferably from 50 to 200 bars and over a range of temperatures extending from about 15 K to about 210 K, and preferably 20 K to u, and a thermal insulation envelope in which the container is disposed.
Thanks to these characteristics, for example for hydrogen, it is possible to process large quantities of gas in a short time by means of conventional compression installations of high flow rate, without the ortho-para transformation which is highly consumptive of energy, and by using cylinders of relatively low weight using materials conventionally selected.
The invention can moreover have one or several of the following characteristics:
the container comprises means for recovering cold from the expansion of the gas;
the container is provided with means forming a heat exchanger adapted to be used before its filling with cold gas so as to cool it before its filling;
the container comprises an outlet conduit provided with an outlet control valve, and the means ensuring a closeable calibrated loss comprise a parallel branch on the valve;
the device comprises several containers within an envelope;
the device comprises at least one container within a Dewar container, other than the container, of liquid nitrogen;
the container contains a gas at a pressure of the order of 200 bars;
the container contains hydrogen in gaseous phase, and at a temperature comprised in a range extending from about 40 K to 120 K;
the container contains hydrogen in gaseous phase, and at a temperature of the order of 80 K, for example 77 K;
the container contains helium in gaseous phase, and at a temperature comprised within a range extending from about 20 K to 80 K;
the container contains neon in gaseous phase, and at a temperature comprised in a range extending from about 50 K to about 70 K;
the container contains carbon monoxide in gaseous phase, and at a temperature comprised in a range extending from about 140 K to 200 K; and
the container contains methane in gaseous phase, and at a temperature comprised within a range extending from about 145 K to 200 K.